EP1525165B1 - Method for producing insulating materials on the basis of mineral fibers - Google Patents

Description

The invention relates to a process for the production of insulating materials from mineral fibers, in particular from glass and / or rock wool, in which in a melting unit, in particular a cupola, a silicate melt produced and defibrated in a defibration in preferably microfine fibers, the fibers preferably binders and / or impregnating agents are added and the fibers are deposited on a conveyor as a nonwoven.

Mineral fiber insulation is made from silicate melts. For this purpose, a silicate starting material, for example glasses, natural or artificial rock is fed to a smelting unit, for example a cupola or a shaft furnace. The silicate melt obtained therefrom is then fed to a defibering unit in which the silicate melt is defibered into microfine mineral fibers. The mineral fibers then fed to a collecting chamber are generally wetted with binding and / or impregnating agents and deposited on a conveying device arranged below the collecting chamber, as a rule this is a conveyor belt. The wetted with binding and / or impregnating mineral fibers form on the conveyor a mineral fiber fleece, which is processed in downstream thermal and / or mechanical devices in a conventional manner to produce insulating materials in the form of sheets, plates, moldings or the like. As a result, mineral fiber insulation materials consist of vitreous solidified fibers, which are connected pointwise with small binders.

In mineral fiber insulating materials, those made of glass wool are distinguished from those made of rock wool. Glass fiber mineral fiber insulation materials are made from silicate melts with relatively high proportions of network transducers, especially alkalis and boron. The raw materials are melted in oil or gas-fired tank furnaces. The fiberization takes place for example by means of the so-called TEL method, in which the melt under the influence of centrifugal forces through openings in the walls of a rotating body slides. This process produces relatively long and smooth fibers.

Rock wool insulation materials were originally melted from rocks such as diabase, basalt and limestone, dolomite. In the meantime, it has increasingly been decided to replace these natural rocks by artificial rocks or to feed them together with artificial rocks to the melting process. In particular, waste from production is processed in these artificial rocks, and the waste can also consist of solidified melts which are produced during the regular emptying of the smelting unit. In addition to this waste, faulty production batches are also processed. The waste is crushed in a first step, then mixed with Portland cement as a binder and stone chips and finally pressed into artificial rocks, so-called shaped stones.

The coarse-grained rocks and / or the correspondingly shaped blocks are filled together with coarse coke as a primary energy source in the melting aggregate, usually in the cupola. Furthermore, additives are added which have a particle size range of about 80 to 200 mm. By applying the raw material coke column from below, d. H. according to the countercurrent principle with the air required for the combustion of the coke is burned above the furnace bottom. In the area of air induction, the furnace temperature reaches a level at which the rocks and aggregates melt. The proportion of glassy solidified waste increases the melting rate. Towards the top, the temperature in the furnace drops, as the heat energy is released to the rocks and the primary energy source. At the same time, the oxygen content in the furnace decreases.

Subsequent heating of the exhaust air converts harmful carbon compounds into less harmful or harmless compounds. The energy content of the exhaust air is then released by means of heat exchangers to the combustion air.

The molten constituents of the raw materials introduced into the melting unit sink to the bottom of the melting aggregate. It comes here to a Saing, in which the iron reduced mainly from the rocks on the ground collects and required for the production of fibers, specifically lighter melt is discharged through a arranged above the bottom outlet. The melt discharged here is then fed to a defibration unit and defibered. Only 50% of the melt supplied to the fiberizing aggregate is converted into fibers. The coarser non-fibrous components are separated from the fibrous components by air classification.

The iron accumulating in the area of the soil must be drained regularly. During deflation of the iron fiber production is interrupted. The melt contained in the melting unit at this time is not suitable for the direct production of insulation materials after re-starting the melting unit and is therefore treated as waste in the course of recycling and fed to production.

In the melting process, which is usually carried out in cupola furnaces, there is a strong dependence between the viscosity and the temperature. Furthermore, the nucleation number and thus the tendency to crystallize is very high. These properties lead in the formation of mineral fibers on so-called cascade spinning machines to relatively short and intermingled mineral fibers. The individual mineral fibers themselves are glassy solidified. Due to their composition, the temperature resistance of the mineral fibers from a molten rock is higher than with glass wool insulation materials.

Of importance in the production and evaluation of mineral fibers is the biosolubility, ie the residence time of the mineral fibers in the human organism. The biosolubility of insulation materials made of rock wool is significantly influenced by the content of Al ₂ O ₃ . With increasing proportions of Al ₂ O ₃ increases on the one hand, the temperature resistance of the fibers and on the other hand, in a surprising manner, the biosolubility.

A typical composition of biolubricated rockwool mineral fibers has a content of SiO ₂ between 35 and 43 mass%, an Al ₂ O ₃ content of 17.5 to 23.5 mass%, a TiO ₂ content of 0.1 to 3 mass%, a content of FeO of 1.7 to 9.3 mass%, a content of CaO + MgO of 23.5 to 32 mass% and a content of K ₂ O + Na ₂ O of 1.3 up to 7% by mass.

For the economics of mass-produced insulating materials made of rock wool, the use of raw materials is significant, which have a high proportion of Al ₂ O ₃ . Although natural rocks often contain aluminosilicates, these are often not present in the required concentrations or only together with unwanted minerals. In contrast, calcined bauxites are relatively expensive. For this reason, waste materials are often recycled, which were previously often solely landfillable and represent the not insignificant risks to the environment because of the content of soluble substances. At the same time, these residues, which are obtained, for example, in rockwool production, are almost completely recycled in the form of melt residues, separated, non-fibrous particles, filter dusts, faulty productions or the like in a primary residue cycle. These residues are processed prior to their use in accordance with the requirements of the mechanical device, in particular the melting units. For example, the residues are comminuted for recycling and mixed in different particle sizes with each other or with other splittigen raw materials, mixed with binders such as cement and pressed into sufficiently large moldings before these moldings are supplied as lumpy raw materials a shaft furnace or a cupola. From the EP 0 765 295 C1 is known, for example, to bind suitable shaped bodies of fine-grained raw materials with the aid of lignin. In the WO 94/12007 Corresponding shaped bodies with molasse-containing binder are described.

As already mentioned, coke is used as the primary energy carrier. The primary energy required for the melting of the raw materials amounts to up to 2 megawatts per tonne of melt. Depending on the origin of the used for coking Coal is the content of inorganic constituents of the coke (ash content) between 6 and 10% by mass. The non-combustible constituents of the coke are incorporated into the silicate melt.

From the US 4,822,388 It is known to replace the coke at least predominantly by a furnace lining of furnaces for the production of aluminum. Here, a complete replacement of the coke is shown as desirable, but at least 60% of the primary energy carrier should consist of the residues of the furnace lining.

Based on this prior art, the object of the invention to further develop a method according to the invention such that a cheaper method can be carried out by the use of inexpensive primary energy, but at the same time provides good melt results without contaminants of the melt.

This object is achieved by a process for the production of insulating materials from mineral fibers, in particular from glass and / or rock wool, in which a silicate melt is produced in a smelting unit, in particular a cupola furnace and is fiberized into a microfine fiber in a defibering device and the fibers a conveying device are stored as a nonwoven, wherein a primary energy source is supplied piece with rocks to the melting unit and arranged like a column in the melting unit, and wherein the fibers preferably binders and / or impregnating agent are added, which is characterized in that is used as the primary energy carrier petcoke, wherein The petroleum coke is used with up to 75% of a mixture with coke.

Residues of almost pure carbon resulting from the thermal cracking of petroleum are used, for example, as firing material in the production of special steels. For example, this is petroleum coke, which is produced in the so-called delayed cooking process, an endothermic process. This process residues from the crude oil distillation, for example, heavy fuel oil are heated quickly in an oven and then introduced in a reaction zone at certain temperature and pressure conditions. The cracked and partially evaporated residue leaving the furnace is converted to volatile hydrocarbons and petroleum coke in the reaction zone. Usually, this petroleum coke is lumpy with particle sizes between 1 and 300 mm.

The petroleum coke to be used according to the invention in the production of insulating materials from mineral tanks is a very hard, crude carbon product with the following characteristic properties: calorific value 30,000 to 40,000 kJ / kg water content ≤ 12% ash content ≤ 1% Volatile stock. ≤ 12% sulfur ≤3,5%

According to a further feature of the invention, it is provided that the petroleum coke partially substituted the usual primary energy source foundry coke in the production of insulating materials from mineral fibers. In this case, a petroleum coke in particulate form with particle sizes between 50 and 300 mm has proved to be particularly advantageous.

Overall, up to 75% petroleum coke can be used as a primary energy carrier, with the remaining 25% still being used as foundry coke.

Preferably, the petroleum coke is further aufkalziniert in the cupola, ie the petroleum coke loses its residual water and enriches the top gas with hydrocarbons. These hydrocarbons lead to an increase in the latent heat in the exhaust gas and are oxidized in subsequent post-combustion plants together with the generated carbon monoxide to CO ₂ . The energy requirement of the post-combustion plants is thereby reduced.

At the same time the petroleum coke passes through temperature zones, which lead to a calcination of petroleum coke. The calcination takes place in an endothermic process, namely a pyrolysis process in which, excluding oxygen or in a reducing atmosphere at temperatures of 1250 to 1500 ° C, a proportion of hydrocarbons is reduced. During the pyrolysis process, the process steps of heating, drying, stripping and sintering take place. At the same time as the calcination, a partial desulphurisation of the coke takes place. However, only the thermally unstable sulfur, which makes up about 50% of the total sulfur content of the petroleum coke, can be removed. An enrichment of the top gases with sulfur-containing compounds can be reduced by additives in the top gas, for example Ca (OH) ₂ , if necessary. According to a further feature of the invention, it is provided that the hydrocarbons released during the heating of the petroleum coke are partly burned and thus contribute to the necessary process heat. The remaining hydrocarbons are burned in the thermal afterburning.

Core of the invention is the substitution of the conventional primary energy carrier by lumpy petroleum coke, wherein up to 75% of the conventional primary energy carrier, such as foundry coke can be replaced by petroleum coke. The petroleum coke is exposed in the cupola different temperature zones through which a natural calcination of petroleum coke is carried out with high density, the petroleum coke in addition to the property of the energy carrier also has a supporting function in Kupolofensumpf.

Further features of the method and the melt according to the invention will be apparent from the subclaims and the following description of a preferred embodiment.

embodiment

A cupola furnace is fed with a lumpy feed material for producing a melt, which in each case consists of half of a primary energy source and rocks as raw material for a silicate melt. The rocks contain 85% artificial stones and 15% natural stones, such as diabase and basalt. The artificial stones consist of 60% recycled material and 40% dismantled mineral fiber insulation materials, wherein the recycling material is taken from the production process in the form of sections or lower-quality products. The artificial stones are pressed from fine-grained material and the solids required for the artificial stones together with rocks used as supporting grain with latent hydraulic substances to lumpy bodies.

The primary energy source consists of 70% petroleum coke and 30% foundry coke.

The petroleum coke has a calorific value of 35,000 kJ / kg, a water content of 8%, an ash content of 0.75%, a sulfur content of 2% and 11% volatiles.

The arranged in the cupola column of raw material and primary energy carrier is supplied in countercurrent principle, the required combustion air, so that the primary energy carrier burns above the shaft bottom. In the area of the introduction of the combustion air, the temperature in the cupola reaches values which are sufficient for the melting of the raw material.

The discharged from the cupola and fed to a fiberizing aggregate melt consists of a proportion SiO ₂ of 38% by mass, a proportion of Al ₂ O ₃ of 22% by mass, a proportion of TiO ₂ of 2.6% by mass, a proportion of FeO of 3.4 mass%, a CaO + MgO content of 31.5 mass% and a K ₂ O + Na ₂ O content of 2.5 mass%. Mineral fibers for insulating materials made from this melt are classified as being biosoluble.

Claims (10)

1. Method for producing insulating materials made of mineral fibers, in particular made of glass and/or stone wool for which a silicate melt is produced in a melting aggregate, in particular a cupola furnace, and is defibrated in a defibrator into preferably microfine fibers and the fibers are placed on a conveyor device as non-woven, whereby a primary energy source is fed lumpy with rocks to the melting aggregate and is placed like a column in the melting aggregate and whereby preferably binding and/or impregnating agents are added to the fibers,
   characterized in that pet coke is used as primary energy source, whereby the pet coke is used with up to 75% of a batch with coke.
2. Method according to claim 1, characterized in that the pet coke has the following properties and/or constituent parts: Calorific value 30000 to 40000 kJ/kg Water content ≤ 12 % Ash content ≤ 1 % Volatile components ≤ 12 % Sulfur ≤ 3,5 %
3. Method according to claim 1, characterized in that the pet coke has a particle size distribution of 1 to 300 mm, in particular of 50 to 300 mm.
4. Method according to claim 1, characterized in that the pet coke is calcined in a cupola furnace in a pyrolysis process.
5. Method according to claim 4, characterized in that the pyrolysis process is carried out under exclusion of oxygen or in a reduced atmosphere at temperatures between 1250 and 1500°C.
6. Method according to claim 4, characterized in that the pet coke is desulfurized during the pyrolysis process.
7. Method according to claim 4, characterized in that hydrocarbon resulting from a calcination and/or sulfur compounds are fed to a blast furnace gas and the hydrocarbon oxidises to CO₂ in a subsequent combustion installation.
8. Method according to claim 7, characterized in that the sulfur containing compounds are reduced in the blast furnace gas by for example Ca(OH)₂.
9. Method according to claim 7, characterized in that parts of the hydrocarbon becoming free during heating up the pet coke are burnt and are used for increasing the process warmth and the remaining hydrocarbons are burnt in a thermal post-combustion.
10. Method according to claim 1, characterized in that the residues of the pet coke are embedded into moulded blocks for producing the melt.